Video: Katrina: What the government knew

WASHINGTON — The terrorist attacks of 2001 changed the priorities and focus of federal emergency planners. Former officials say 9/11 diverted attention from natural
disasters such as Katrina, which had been the primary focus of the Federal Emergency Management Agency (FEMA).

A government document obtained by NBC News shows just how radically the focus shifted to terrorism. It is dated July 2004 and lists 222 upcoming FEMA and homeland security exercises scheduled to prepare for national emergencies. Only two involve hurricanes.

"And even in both of those cases, they're dealing with what would happen if there were a terrorist attack associated with a hurricane event," says NBC News analyst William Arkin.

What's more, it appears that the federal government did not follow up on an exercise last year that mostly predicted what happened in New Orleans — devastating flooding and hundreds of thousands stranded.

The scenario was dubbed Hurricane Pam: 120 mph winds, a massive storm surge, 20 feet of water in the city, 80 percent of buildings damaged, refugees on rooftops, possibly gun violence that would slow the rescue.

"What bothers me the most is all the people who've died unnecessarily," says Ivor Van Heerden, a hurricane researcher from Louisiana State University who ran the exercise.